Unidirectional transmission members and inverter devices are already routinely used in automatic winding timepiece movements, notably being disposed in the automatic winding train of the barrel spring. For example, different embodiments of such devices are described in pages 180 et seq of “Théorie d'horlogerie”, by C.-A. Reymondin et al., published by Fédération des Ecoles Techniques (Suisse), ISBN 2-940025-10-X.
Two types of wheel are used in these devices, namely some intended to cooperate with a unidirectional transmission member in an axial direction and others intended to cooperate with a unidirectional transmission member in the general plane of the wheel. In the first case, the wheels have structures that are generally simpler than in the second case, but the corresponding devices have a larger overall size. However, when the cooperation between the wheel and the unidirectional transmission member occurs in the general plane of the wheel, it is necessary to machine detents or tips in the wheel, generally by complex milling operations, which can prove costly. This drawback is all the more of a problem when two wheels are necessary to produce an inverter device in the same timepiece movement.
Furthermore, the aforementioned work gives an example of an inverter device comprising two unidirectional transmission systems arranged one alongside the other, thus having a non-negligible overall size within the corresponding timepiece movement.
The patent CH 331124 gives an example of an inverter device in which two unidirectional transmission systems are arranged coaxially with each other to reduce the overall size of the inverter device. However, the structure of the components used in this device is complex and likewise their assembly.
Moreover, it will be noted that these devices are not generally used in the manual winding train, in which a clutch mechanism is generally used, to prevent rotation of the winding stem when the barrel is driven from the automatic winding mechanism.